Bulletin 151, Truck and Garden Insects


ticularly to late-planted vines. Farmers in some communities
have abandoned the attempt to grow a late crop on account of
the ravages of this pest. With this insect, like all whiteflies,
it is the larva which does the damage by sucking the sap from
the leaves. The adult, which is smaller than the citrus whitefly,
lays her eggs on the under side of the leaves. These hatch in
about a week. The young crawl about until they find a suitable
place to insert their probosces or beaks. Having once inserted
them, they are unable to withdraw and are anchored firmly for
the remainder of their larval days. If the beak is pulled out
forcibly, the larva is unable to reinsert it and will die of star-
vation. These larvae are very flat, roundish bodies about 1/12
of an inch long, attached snugly to the under side of the leaves,
which they resemble so closely in color as to be inconspicuous.
Like the citrus whitefly, these larvae excrete a honeydew, a
sweet substance in which grows a black fungus called sooty
mold. Like that species too, but to a less degree, they are at-
tacked by a bright red parasitic fungus, the red Aschersonia.
 Control.-The larvae can be killed by either a strong soap
solution or kerosene emulsion. This must be applied soon after
the eggs hatch, otherwise the insects will have done their work.
As these larvae are very small when first hatched, it will be
necessary to keep close watch on the plants and spray as soon
as many larvae are seen.

 SWEET-POTATO ROOT-WEEVIL (Cylas formicarius)
 This extremely dangerous pest in tropical countries has
obtained a foothold in many places in Florida. It is a small











 FIG. 107.-Work of sweet-potato root-weevil. (Original.)
snout-beetle which bores thru the roots, ruining them (fig.
107, even for stock food. The weevil attacks the potatoes in